(Newser)
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Kids may turn their parents' hair gray, but they may also add years to those parents' lives. Researchers in Sweden analyzed data from more than 700,000 men and 725,000 women born between 1911 and 1925, and going back that far was the point: Participants in the study were followed from age 60 until their death, or until 2014 if that came first, and the researchers were specifically curious whether the inverse association between having kids and death risk "increased at older ages when health starts to deteriorate and the need of support from a family member increases." What they found, per their study in the Journal of Epidemiology & Community Health: yes.

As Live Science reports, at 60, men with at least one child had a 1.35% chance of dying within a year; for childless men, it was 1.41%. That's a 4% increased risk for the latter group. But by age 90, the risk for the childless group was 9% greater. Some other findings: the gender of the child had no bearing on things, and the difference in death risks ws a bit larger for men than for women. The association was also greater when looking at the unmarried, perhaps because a spouse can provide "care and support, whereas the non-married and widowed would be more exclusively dependent on their adult children." Still, researchers say other factors may be at play, including the possibility that parents practice healthier habits than nonparents. (Research suggests big broods make for happy parents.)